Abstract\nWe consider a dual ?-system under double laser excitation to investigate the possibility of indirect coherence transfer between atomic ground states through an excited state. The atomic system is excited by a frequency modulated pump laser and probed by a low-power cw laser. All the decoherence mechanisms are discussed and taken into account. Adjustment of parameters of the two radiations aimed at maximization of coherence transfer is addressed. The study can help to understand phenomena as collisional transfer of coherence and can find application in the experimental realization of atomic sensors.
Na atoms in the magnetic field have been selectively excited to each Zeeman sub-level of either the 3p2P1/2 or 3p 2P3/2 state by a tunable dye laser and the Zeeman spectra of the fluorescence from the collisional populated 3p 2P levels have been measured. From the intensities of the Zeeman lines, the selectivity in the collisional transitions between the Zeeman sub-levels of the 3p 2P1/2 and 3p 2P3/2 states has been directly specified. The time evolution of the σ-polarized fluorescence intensity of the Na(3p 2P1/2→ 3s 2S1/2) transition has been measured following the Na(3p 2P3/2â†� 3s 2S1/2) excitation by a σ-polarized short light pulse at H= 129 G. An amplitude modulation was found in the fluorescence from the collisional energy transferred state Na(3p 2P1/2). This is the first observation of quantum beats in collision-induced fluorescence. The frequency of the modulation coincides very well with that of the quantum beats of the resonance fluorescence Na(3p 2P3/2→ 3s 2S1/2), but the phases are opposite. These results are explained by assuming the conservation of coherence during collisional energy transfer.
Collisional excitation transfer and relaxation of K 5
sp2P atoms in collisions with noble gases, as well as the radiative lifetimes of the K 5P, 6P and 7P fine-structure states have been investigated by methods of atomic fluorescence spectroscopy. Potassium vapour was mixed in a cell with a noble gas and selectively excited by pulsed dye-laser radiation to the 5
sp2P
sb1over2 or the 5
sp2P
sb3over2 state in zero magnetic field and to the 5
sp2P
sb1over2−1over2 or the 5
sp2P
sb3over2−3over2 Zeeman substate in a field of 70 kG. Interferometric analysis of the fluorescence emitted from the directly (optically) excited state and that emitted from the collisionally populated states allowed the determination of the fine-structure mixing cross sections for collisions with He, Ne, Ar, Kr and Xe in zero magnetic field. Excitation transfer between Zeeman substates was investigated for collisions between the selectively excited 5P atoms and He, Ne and Ar atoms, allowing the determination of the multipole relaxation (depolarization) cross sections for dipole, quadrupole and octupole decay, as well as the Zeeman and fine-structure mixing cross sections and orientation transfer cross sections. A comparison of theoretical calculations with the experimental data has been made and the rate equations governing multipole relaxation and including effects due to strong fine-structure mixing on the multipole relaxation, have been described in detail. The radiative lifetimes of the individual fine-structure components of the K 5P, 6P and 7P states have been determined experimentally by means of time-resolved laser-induced fluorescence techniques. These data are compared with numerous theoretical calculations and the available experimental values.Dept. of Physics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1988 .B474. Source: Dissertation Abstracts International, Volume: 49-04, Section: B, page: 1223. Thesis (Ph.D.)--University of Windsor (Canada), 1988.